Broken Saucy update on a Zenbook

Confession: I did a somewhat rash Kubuntu Saucy upgrade while on holidays. It left me with a blank screen at startup. But what better entertainment can you have lying awake with a 6 hour jet lag at 4am than fixing your Linux?

The issue, by the way, is the Zenbook (UX31A) not liking the new kernel. The solution is Joseph Salisbury's inofficial kernel fix.

First thing: get a command line and an internet connection. For this, I booted into Recovery Mode and chose the 'root' option.

mount -o remount,rw /
#cd into some convenient directory, as we're writing a file next
wpa_passphrase <essid> <passphrase> > wpa.conf
ifconfig wlan0 up
#if you don't know your driver (mine is the generic wext),
#try 'wpa_supplicant --help'
wpa_supplicant -Dwext -iwlan0 -cwpa.conf &
dhclient wlan0
wget http://kernel.ubuntu.com/~jsalisbury/lp1195483/linux-image-3.11.0-12-generic_3.11.0-12.19~lp1195483v2_amd64.deb
wget http://kernel.ubuntu.com/~jsalisbury/lp1195483/linux-image-extra-3.11.0-12-generic_3.11.0-12.19~lp1195483v2_amd64.deb
dpkg -i linux-image-3.11.0-12-generic_3.11.0-12.19~lp1195483v2_amd64.deb linux-image-extra-3.11.0-12-generic_3.11.0-12.19~lp1195483v2_amd64.deb

I exited the rescue system and rebooted (note: the 'resume' option doesn't work yet, you need a proper shutdown) and got my system back. Hooray!

The new kernel needs to be protected against upgrades:

sudo apt-mark hold linux-image-3.11.0-12-generic
sudo apt-mark hold linux-image-extra-3.11.0-12-generic

Sources:

• Recovery mode: wiki.ubuntu.com/RecoveryMode
• WPA from command line: linux.icydog.net/wpa.php, askubuntu.com/questions/104066/enable-wifi-in-recovery-terminal
• Kernel fix: bugs.launchpad.net/ubuntu/+source/linux/+bug/1195483